MATLAB: How do i change StepTolerance

constraintsfminconsteptolerance

Hi,

Please i would like to write a code in matlab that changes the StepTolerance to 1E-20 but i do not know how to go about.

Please can someone assist, please..

This is my script:

y0=[0.02352;0.00048;0.0288;0.00432;0.216;0.1104;0.1104;2;2;2;55;50;0.5];

h=0.0006944444;

tSpan=[0 535];

options = optimoptions('StepTolerance', 1e-20);

[tSol, ySol]=ode23tb(@(t, y) MBBRFun4(t,y), tSpan, y0, options);

as it stands, i get the following error:

Warning: Failure at t=6.848966e-01. Unable to meet integration

tolerances without reducing the step size below the smallest value

allowed (2.433242e-15) at time t.

Thanks in advance

Best Answer

Hi,

As I have attached an example code for changing step tolerance. Hope it helps your cause.

Related Solutions

MATLAB: How can i extract data of specific dates in a big excel file and save in a different excel file

It might be useful to use Tall Arrays. These arrays are not completely loaded into memory if they are really big.

I would recommend to go to https://uk.mathworks.com/help/matlab/import_export/tall-arrays.html

Amid.

MATLAB: Solving DAEs ,errors happen ,i do not know why

Does this work ?

function mainsolve
M=[1 0 0 0
   0 1 0 0
   0 0 0 0
   0 0 0 0];
y0=[1 0 0.984 0];
tspan=[0 1];
options = odeset('Mass',M,'RelTol',1e-4,...
                 'AbsTol',[1e-6 1e-6 1e-6,1e-6],...
                 'Vectorized','on');
[t,y] = ode15s(@ct,tspan,y0,options);
plot(t,y)
function dy=ct(r,y)
dy=[-8*y(1)+8*y(3)+0.2*(1-y(2))*exp(20-20/y(1))
    -8*y(2)+8*y(4)+0.2*(1-y(2))*exp(20-20/y(1))
    -4*y(1)+5*y(3)-0.92
    -4*y(2)+4*y(4)];

Best wishes

Torsten.

Related Question

Fitting experimental data to ODE add additional fitting parameter which should not be integrated by ODE-Solver